In recent years, various attempts at disposing objects having various functions on an inner circumferential surface and the like of a pneumatic tire have been made.
For example, an attaching method has been proposed in which tire tags (radio frequency identification tags, for example), chips, or the like are attached to an inner liner or the like of a green tire using a so-called surface fastener such as a hook and loop fastener or a hook and hook fastener (see Japanese Unexamined Patent Application Publication No. 2005-517581A).
Additionally, a pneumatic tire has been proposed in which a surface fastener is vulcanization bonded to a region corresponding to a tread portion of a tire inner surface, and a noise absorbing member is attached to the tire inner surface via the surface fastener (see Japanese Unexamined Patent Application Publication No. 2006-044503A).
The surface fasteners proposed in Japanese Unexamined Patent Application Publication Nos. 2005-517581 and 2006-044503A are preferable in that a relatively strong engagement force is realized when attaching an object, and engagement on a surface can be achieved without slight misalignments becoming a problem during attachment.
However, with surface fasteners, a state in which the individual engaging elements of the surface fastener are engaged is not ideal due to the inner circumferential surface of the pneumatic tire being an annular, curved surface. With surface fasteners, portions of the edges and center portions become raised, and an amount of obtained engagement force varies (positional variation within the tire and variation from tire to tire). As a result, in some cases, the expected engagement force is not obtained. Additionally, partial physical deterioration and deterioration/declining over time of the engagement force of an entirety of the surface fastener accompanying the progression of the partial physical deterioration occur as a result of repetitive deformation and compaction over an extended period of time caused by rolling motion at high speeds in a state of relatively elevated temperatures. This has led to cases in which difficulties have been met in maintaining a desired engagement force over an extended period of time.
Furthermore, while it may be said that the surface fastener is preferable in that engagement on a surface is achieved without slight misalignments and the like becoming a problem during attachment, when the attached object with functionality is a precision measurement instrument or the like, the attached position needs to be more accurate and precise. From such a viewpoint, there are objects with functionality not geared toward attachment by a surface fastener.
Meanwhile, the present inventors have previously proposed joining a mechanical fastener called a hook or a snap to a tire inner surface and attaching various objects having a desired function via the mechanical fastener (see Japanese Unexamined Patent Application Publication Nos. 2012-25318A, 2012-25319A or 2012-240465A) as a pneumatic tire in which an obtained engagement force is great and essentially free of variations (positional variation within the tire and variation from tire to tire); the engagement force deteriorates/declines minimally over time due to extreme usage conditions including repetitive deformation and compaction over an extended period of time caused by tire rolling motion at high speeds in a state of relatively elevated temperatures; and the desired engagement force can be maintained over an extended period of time.
Specifically, as described in the claims of Japanese Unexamined Patent Application Publication No. 2012-25318A as a representative, the inventors have previously proposed a pneumatic tire having a first fastener of a separable pair of mechanical fasteners, such as a hook or a snap, disposed on a tire inner surface (claims of Japanese Unexamined Patent Application Publication No. 2012-25318A (claim 1)). More specifically, the inventors have previously proposed a pneumatic tire, wherein the first fastener is made of at least two components, the two components being fixed and forming the first fastener by sandwiching a tire member or a tire reinforcing member (claims of Japanese Unexamined Patent Application Publication No. 2012-25318A (claim 2)).
According to the method of joining a mechanical fastener called a hook or a snap to a tire inner surface and attaching a desired object described in Japanese Unexamined Patent Application Publication Nos. 2012-25318A, 2012-25319A or 2012-240465A, it is possible to engage and attach the object to the tire inner surface via the mechanical fastener. Then, according to the method, generally the obtained engagement force is great and free of variations (positional variation within the tire and variation from tire to tire), and the object can be attached in a predetermined position with favorable accuracy. As a result, a pneumatic tire having minimal deterioration/declining over time of the engagement force as a result of extreme usage conditions repeated over an extended period of time, and the capability of maintaining the desired engagement force over an extended period of time was achieved. Moreover, a superior pneumatic tire capable of causing the desired object with a specific function to exhibit the function with favorable accuracy over an extended period of time was achieved.
In particular, when the first member of the mechanical fastener attached to the tire inner surface is a fastener having at least two components, the two components being fixed and forming the first fastener by sandwiching a tire member or a tire reinforcing member, the fixed state is even more robust, resulting in an even more superior mechanical fastener having favorable durability.
However, the pneumatic tire according to the above method is a tire having an object with a specific functionality attached by essentially one mechanical fastener and, as the tire rolls at high speed, the object with a specific functionality attached to a tire lumen may rotate about the mechanical fastener as a rotation central axis. Then, when such a rolling motion is started, the rolling motion may give rise to failure, damage, or the like of the object with a specific functionality, making it no longer possible to continue accurate measurement.